1. Field
One embodiment of the present invention relates to a caption detection device and a caption detection method for detecting existence of a caption in a video frame and a pull-down signal detection apparatus in which the caption detection device and caption detection method are used.
2. Description of the Related Art
As is well known, frequently the caption for displaying a script spoken by an actor and the like is provided in a lower portion of a screen in a video signal frame of a movie and the like. Because such pieces of caption information possibly have an influence in inspecting a video signal, sometimes it is necessary to confirm whether or not the caption information is currently included in the video signal frame.
For example, in a caption detection method disclosed in Jpn. Pat. Appln. KOKAI Publication No. 8-212231 (Patent Document 1), an image is divided into plural regions, a feature amount of the caption is computed in each region, a determination whether or not the caption is included in each region is made based on the feature amount, the number of regions having the captions is projected in a row direction and a column direction, and a determination whether or not the caption is included in the image is made based on the projection result.
However, in the caption detection method disclosed in Patent Document 1, because of the determination whether or not the caption information is included in the screen at a certain moment, there is a problem in that a distinction between video motion and the caption is hardly made in determining how much motion exists in the video signal frame.